Extraction, determination and metabolic profiling of alkaloids in traditional Chinese medicines by modern analytical techniques

Abstract

This dissertation is broadly divided into two parts. Part I focused on the isolation and determination of pyrrolizidine alkaloids (PAs) in traditional Chinese medicine with modern analytical techniques. Different methods of extraction such as microwave-assisted extraction and pressurized hot water extraction have been applied. The extraction efficiencies were compared with traditional method and analyzed by LC/MS. The effect of ion suppression in the botanical extracts was investigated. Concurrently, a non-aqueous capillary electrophoresis (NACE) technique with on-column preconcentration was developed for the separation and determination of PAs. Part II focused on the metabolic profiling study of the natural alkaloid, named berberine, in rats with GC/MS, LC/MS and 1H NMR. A new targeted data processing method for LC/MS was applied. The reliability of the new method was proven by compared with 1H NMR (non-targeted). The results obtained gave a further comprehensive picture of the metabolic changes induced by berberine in rat.